The present invention relates to a submarine cable grapnel for grappling a submarine cable on the bottom of the sea for recovery onto a cable ship.
In case of recovering a failing submarine cable, a cable grapnel is paid out from a cable ship down to the bottom of the sea and is dragged in a direction substantially perpendicular to that in which the cable is laid on the seabed, and the failing cable grappled by the grapnel is pulled up onto the cable ship for repair.
The conventional submarine cable grapnel poses the following problems when using the grappling unit singly. First, when the cable grapnel is brought down to the bottom of the sea, the grappling unit often spins and hence cannot land on the seabed in a normal attitude in which the grappling hook digs up the seabed. Second, when the grapnel is dragged, the grappling hook often rotates on the seabed and cannot maintain its normal attitude in which the hook digs up the seabed.
One solution that has been proposed to solve these problems is to connect four grappling units with their hooks spaced apart an angular distance of 90.degree. about the axis of grapnel. However, this structure calls for four grappling units and hence is at least four times as expensive as one grappling unit, and maintenance and repair work of the grapnel 10 also becomes four-fold accordingly.